The Home-made Home-builders Engine

On Sat, 30 May 2009 10:11:39 -0500, Charles Vincent
wrote:

Veeduber wrote:
On May 29, 3:12 pm, Charles Vincent wrote:

They do have an OHV version I believe. At the RPM's these engines run
at i.e. direct drive prop, I am not sure the L head is that much of a
compromise.
----------------------------------------------------------------------------------------

All of the Pobjoy's were geared, OHV engines. They produced 80hp @
3300 rpm (prop speed of 1400rpm). Weight was 130 lbs.

-R.S.Hoover


I was referring to the HCI Radials which are ungeared. I have seen the
Pobjoy. I have collected everything I can get my hands on with regard
to small radial engines. I have even managed to find factory blueprints
for parts of the Kinner and a Leblonde. No prints sadly for the Pobjoy,
just some contemporaneous technical reviews that do have three views of
the engine. There was a Pobjoy on display in a museum outside San Jose,
but that is a trek from your 20.

Charles

I will post some scanned photos of a sectioned pobjoy on
alt.binaries.pictures.aviation in the near future.

I thought I had cracked the problem when I discovered that the Pobjoy
R was made under licence by Walter as the Walter Mira.
an email to Walter caused some searching among the old retired
employees and one was able to confirm that the tooling and all the
drawings were destroyed in WW2 when the factory was the target of an
allied bombing raid.

bugger the war!
Stealth Pilot

Yes indeed, striving for the (all but) impossible is always a noble
task.
I'm in a completely different frame of mind, I'm concentrating on
building my first airplane and working out a powerplant isn't one of
the new experiences I want to tackle, and getting a pilot's license
will probably be hand along the way as well. (Yep, I'm doing it
backwards. ;^)

Just to be a devil's advocate for a moment, if one were to add $1 per
hour for all the time used thinking about it, plus all the actual
money spent testing out ideas, that $2000 engine might be a lot closer
to $10K than anyone is willing to admit. Nonetheless "Because I want
to" is a phrase that has no intrinsic value, and yet is worth a
million bucks to whoever says it.

I'll continue to follow this thread with interest, please return to
your regularly scheduled brainstorming.

Cheers
Gerry


Briefly, the homebuilder would be overjoyed to find a device that's
dirt-cheap, rock-solid, as reliable as taxes, and oh: pretty would be nice.
* * * That's a hard prescription to fill, but the faithful keep thinking
and looking. $2K would be nice - $10K isn't.

Brian W

Gerry,

I agree with you about the amount of time being wasted.

Especially, I suspect that the series of threads have worked their way
around to a search for a "traditional" direct drive "real" airplane
engine--with an implied resolution to build one if it can not be purchased
new at an unrealistic discount.

Actually, there have been any number of successfull installations of higher
reving engines with multiple v-belt reduction systems. They are probably
not especially energy efficient, and the belts are quickly destroyed if the
propeller windmills in flight with the engine stopped; but they are a cheap
and light weight way to get the job done and are easily inspected.

Personally, I really don't "like" that solution; but it is well proven for
relatively low power; but cheap and easy to inspect can save you a lot more
than a little lower friction for personal use of a small sport aircraft.
So, I would have to seriously consider that as my solution for less than 80
horsepower if I needed an engine at the present time.

As you say, it has become a nearly complete waste of time, and I expect my
own contributions to be few and far between for the forseeable future.

Peter


"Gerry van Dyk" wrote in message
...
Yes indeed, striving for the (all but) impossible is always a noble
task.
I'm in a completely different frame of mind, I'm concentrating on
building my first airplane and working out a powerplant isn't one of
the new experiences I want to tackle, and getting a pilot's license
will probably be hand along the way as well. (Yep, I'm doing it
backwards. ;^)

Just to be a devil's advocate for a moment, if one were to add $1 per
hour for all the time used thinking about it, plus all the actual
money spent testing out ideas, that $2000 engine might be a lot closer
to $10K than anyone is willing to admit. Nonetheless "Because I want
to" is a phrase that has no intrinsic value, and yet is worth a
million bucks to whoever says it.

I'll continue to follow this thread with interest, please return to
your regularly scheduled brainstorming.

Cheers
Gerry


Briefly, the homebuilder would be overjoyed to find a device that's
dirt-cheap, rock-solid, as reliable as taxes, and oh: pretty would be
nice.
That's a hard prescription to fill, but the faithful keep thinking
and looking. $2K would be nice - $10K isn't.

Brian W

"Peter Dohm" wrote in message
...
Gerry,

I agree with you about the amount of time being wasted.

Especially, I suspect that the series of threads have worked their way around
to a search for a "traditional" direct drive "real" airplane engine--with an
implied resolution to build one if it can not be purchased new at an
unrealistic discount.

Actually, there have been any number of successfull installations of higher
reving engines with multiple v-belt reduction systems. They are probably not
especially energy efficient, and the belts are quickly destroyed if the
propeller windmills in flight with the engine stopped; but they are a cheap
and light weight way to get the job done and are easily inspected.

Personally, I really don't "like" that solution; but it is well proven for
relatively low power; but cheap and easy to inspect can save you a lot more
than a little lower friction for personal use of a small sport aircraft. So, I
would have to seriously consider that as my solution for less than 80
horsepower if I needed an engine at the present time.

As you say, it has become a nearly complete waste of time, and I expect my own
contributions to be few and far between for the forseeable future.

The more I think about it, I think the Harley is the perfect choice. High HP,
air cooled, available from crashed bikes, built with a separate crankcase,
designed with a belt drive to be used, many sizes available.
--
Jim in NC

"Morgans" wrote in message
news

The more I think about it, I think the Harley is the perfect choice. High
HP, air cooled, available from crashed bikes, built with a separate
crankcase, designed with a belt drive to be used, many sizes available.

I am not sure if the Harley engine is perfect or not, but to your list I
would add that virtually every part and even brand new whole "clone" Harley
engines are available from several sources in addition to Harley Davidson
itself.

Not cheap, not so available, but what about the various BMW motorcycle
engines?

Vaughn

On Fri, 05 Jun 2009 01:08:03 GMT, "vaughn"
wrote:


"Morgans" wrote in message
news

The more I think about it, I think the Harley is the perfect choice. High
HP, air cooled, available from crashed bikes, built with a separate
crankcase, designed with a belt drive to be used, many sizes available.

I am not sure if the Harley engine is perfect or not, but to your list I
would add that virtually every part and even brand new whole "clone" Harley
engines are available from several sources in addition to Harley Davidson
itself.

Not cheap, not so available, but what about the various BMW motorcycle
engines?

Vaughn


bmw engines need only a modified rotax gear head fitted to them to be
usable.

On Jun 4, 10:30*am, "Peter Dohm" wrote:
Gerry,

I agree with you about the amount of time being wasted.

Especially, I suspect that the series of threads have worked their way
around to a search for a "traditional" direct drive "real" airplane
engine--with an implied resolution to build one if it can not be purchased
new at an unrealistic discount.

Peter, I certainly want to be more careful about calling it "wasted
time". If one succeeds the time is certainly not wasted is it? My
only real point is to caution everyone about how much that "Cheap /
Inexpensive" engine actually cost in real life. I'm sure that there's
been more than one occasion where that engine proved to cost more than
an off-the-shelf airplane engine. All the Eggenfellners, Vestas,
Aerovees, Real World Solutions and other conversion engines of the
world started with a guy and an idea. No-one who gives such a
conversion a swing need justify to us on the sideline why they're
doing it.

Cheers
Gerry

"Gerry van Dyk" wrote in message
...
On Jun 4, 10:30 am, "Peter Dohm" wrote:
Gerry,

I agree with you about the amount of time being wasted.

Especially, I suspect that the series of threads have worked their way
around to a search for a "traditional" direct drive "real" airplane
engine--with an implied resolution to build one if it can not be
purchased
new at an unrealistic discount.

Peter, I certainly want to be more careful about calling it "wasted
time". If one succeeds the time is certainly not wasted is it? My
only real point is to caution everyone about how much that "Cheap /
Inexpensive" engine actually cost in real life. I'm sure that there's
been more than one occasion where that engine proved to cost more than
an off-the-shelf airplane engine. All the Eggenfellners, Vestas,
Aerovees, Real World Solutions and other conversion engines of the
world started with a guy and an idea. No-one who gives such a
conversion a swing need justify to us on the sideline why they're
doing it.

Cheers
Gerry

Exactly right. The "fun factor" of making your own design, or adaptation,
work well has to be part of the equation.

By the way, I must admit that I was at least partially wrong in my advocacy
of a multiple v-belt reduction drive. The darned things can loose a lot of
traction when wet, so that will require a lot more thought.

Peter